PROJECT SUMMARY African-American populations are disproportionately impacted by Alzheimer?s disease and related dementias (ADRD). Existing evidence suggests that a complex interplay of mechanisms contribute to elevated risk, including structural inequities in education, income, and community resources. What is not known is whether the undue burden of ADRD can be partly explained by exposure to community violence over the lifecourse. The current older adult population of African-Americans experienced an epidemic of violence and incarceration in their childhood to midlife years, with ongoing racial disparities even as violent crime overall has declined. Exposure to community violence is associated with multiple ADRD risk factors, including toxic stress, lower educational attainment, poor mental health, substance use, hypertension and obesity. Furthermore, African- American communities are subjected to structural violence, i.e. the extent to which community violence is sanctioned or created by racism in policies and programs. The overall objective of this study is to examine whether exposure to community and structural violence over the lifecourse is associated with cognitive function and ADRD among older African-Americans. The central hypothesis is that violence exposure at key developmental periods, e.g. childhood and adolescence, as well as lifetime cumulative exposure, lead to increased risk of cognitive decline and ADRD. The study will leverage two longitudinal cohorts, the Study of Healthy Aging in African-Americans (STAR) and the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE), which have data on social and behavioral measures, five decades of health records, and residential history of participants at several time points from birth until later life. We will use publicly available historical crime, incarceration and demographic data to address the following aims: 1) Examine associations between community and structural violence exposure at multiple time points, and cognitive decline and ADRD incidence; 2) Examine associations between violence exposure, and social, behavioral and health risk factors for cognitive decline and ADRD; and 3) Delineate the interplay between community and structural socioeconomic disadvantage, violence exposure, and cognitive decline and ADRD. We will conduct cross- sectional and longitudinal analyses of cognitive function, decline and ADRD incidence. African-Americans are disproportionately represented in the ADRD epidemic and yet very little is known about how community and structural violence may contribute to brain aging. It is critical from a public health standpoint to identify how policies affecting childhood and adult exposures can mitigate ADRD risk and cognitive decline in later life.